The wall jump was originally a technique that certain characters, such as Pikachu and Sonic, were able to perform in Super Smash Flash 2. Wall jumping was not present in Super Smash Flash due to the limited physics of the game. Wall jumping is when a character, who is close to a wall, is able to jump off of it. As of Beta, the feature has been removed entirely.

However, while only a handful of characters were able to perform a wall jump, all characters are able to perform a wall tech jump.

Trivia

Sonic[1] and Pikachu were both able to wall jump in SSF2 demo v0.8b. However, there were no wall jump animations, Pikachu could do only one, Sonic's got weaker every time he wall jumped without touching the ground (like in Brawl), and they could do it only in Central Highway and Twilight Town. In v0.9, Sonic and Pikachu can only wall jump on Central Highway on the right side of the bridges. There is a glitch that makes Sonic wall jump on one of the bridges that disappears making it look like he is wall jumping off the air.